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RAS Lab Review

Decent Essays

RAS proteins are well understood in terms of their function, molecular structure and most importantly their prevalent role in carcinogenesis. Oncogenic RAS is the single most abundant phenotype seen in cancers seen in almost 30% of human tumours screened (Stafford, Walker and Webb, 2012); with certain mutations in RAS being the single determining factor for carcinogenesis. The role of RAS in signal transduction pathways involved in cellular proliferation, apoptotic evasion and cell survival make RAS a key proto-oncogene vulnerable to oncogenic mutations. (Weinberg, 2014) The structural indications of certain mutations in RAS is widely understood however the preference of different RAS mutational isoforms in certain cancers still requires …show more content…

Numerous experiments on NIH/NT3 mice would later be the determining factor in being able to identify the effects of RAS oncogenes. These experimental animal models provided key information on the types of cancers that RAS oncogenes can cause the frequency of mutations in certain cancers and the different isoforms of RAS. A major breakthrough from 1987 - 1993 started to shed light on the signalling mechanisms of RAS; how RAS is activated by receptor tyrosine kinases, how RAS associates with GEF’S (guanine exchange nucleotide factors) and GAP’S (GTP-ase activating proteins); how RAS is associated with downstream signalling pathways involved in key cellular processes, and how tumour cells harbour oncogenic RAS that has decreased affinity for GDP, causing changes in key processes such as cellular proliferation that initiate cancerous change. These major research experiments along with countless other defining research are what have developed our understanding of the role of RAS in cancer as we know in the modern day. Three major isoforms of RAS; K-ras, H-ras and N-ras oncogenes are most frequently found in human tumours. Oncogenic mutations in upstream mediators or mutations within RAS itself cause RAS to become constitutively active, leading to amplification of signals that lead carcinogenic changes in normal cells. K-ras mutations have been reported in 22% of human cancers and have been reported to be seen most prevalently in pancreatic

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